Novavax‘s updated Covid vaccine won the backing of U.S. regulators on Tuesday, putting the shot on track to roll out weeks after new jabs from Pfizer and Moderna reached Americans.

The Food and Drug Administration authorized Novavax’s single-strain vaccine, which targets omicron subvariant XBB.1.5, for emergency use in people ages 12 and up.

The Centers for Disease Control and Prevention is now including Novavax’s shot in the same recommendation it issued last month for updated vaccines from Pfizer and Moderna. That recommendation says all Americans ages six months and older can receive an updated Covid jab.

Novavax said in a statement that doses of the shot will likely be available within the next few days.

“Novavax’s authorization today means people will now have the choice of a protein-based non-MRNA option to help protect themselves against Covid-19, which is now the fourth leading cause of death in the U.S.,” said Novavax CEO John Jacobs in the statement. “In the coming days, individuals in the U.S. can go to major pharmacies, physicians’ offices, clinics and various government entities to receive an updated Novavax vaccine.” 

Public health officials see Novavax’s vaccine as a valuable alternative for people who don’t want to take messenger RNA shots from Pfizer and Moderna, which teach cells how to make proteins that trigger an immune response against Covid. Novavax’s shot fends off the virus with protein-based technology, a decades-old method used in routine vaccinations against hepatitis B and shingles.

Around 2 million Americans have received the updated Covid vaccines from Pfizer and Moderna so far, the Biden administration said last week, even as patients eager to get their dose have been met with unexpected insurance delays and availability issues.

Regardless, all three shots are expected to help the U.S. combat the spread of Covid this fall and winter, when the virus usually spreads at higher levels. 

The nation is already seeing a surge in cases and hospitalizations. While levels remain far below previous Covid waves in the U.S., it’s still the first notable uptick since last winter and has even prompted the return of mask mandates for a handful of businesses and schools. 

The rise is driven by newer strains of the virus that are gaining ground nationwide as XBB.1.5 gradually declines. That includes EG.5, or Eris, an omicron strain that accounted for 29.4% of all cases as of Saturday, according to the CDC. 

A Novavax spokesperson said last month its new Covid vaccine generated a “broad immune response” against Eris and another fast-spreading strain called XBB.1.16.6 – both of which are descendants of omicron.  

But it’s unclear whether the company’s new vaccine will protect against BA.2.86, a highly mutated omicron strain that health officials are watching closely despite its small number of cases. Novavax last month said it was still testing its vaccine against BA.2.86.

The rollout of Novavax’s new shot comes months after the end of the U.S. Covid public health emergency. 

The end of that declaration means all three manufacturers will sell their updated shots directly to health-care providers and vie for commercial market share.  Previously, the government purchased vaccines directly from manufacturers at a discount to distribute to all Americans for free. 

During the advisory meeting last month, Novavax said the list price of its vaccine is $130 per dose.

Federal and corporate programs are aiming to fill the gap for uninsured Americans. That includes the Biden administration’s Bridge Access Program, which will provide Covid vaccines at no cost to underinsured and uninsured people. 

It’s unclear how many Americans will actually roll up their sleeves and take the new vaccines from Novavax, Pfizer and Moderna.

But roughly 42% of Americans surveyed by the CDC in August said they “definitely will” or “probably will” get a Covid shot this fall, Dr. Megan Wallace, a CDC epidemiologist, said during the advisory meeting.